TABLE 1 in The late Givetian (Middle Devonian) ammonoid Epitornoceras Frech, 1902 from Argentina (southwestern Gondwana)
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TABLE 1. — Comparison of the morphological characteristics of the different species belonging to the genus Epitornoceras Frech,1902.Abbreviations: CWI, conch width index; UWI, umbilical width index; WER, whorl expansion rate; WWI, whorl width index. MorphologicalEpitornocerasEpitornocerascharacters atEpitornocerastransmediterraneumdennisoniEpitornocerasthe adult stageEpitornoceras baldisimithracoidesKorn & Bockwinkel,Kirchgasser,peracutum(c. 30-50 mm dm)(Leanza, 1968)(Frech, 1888)2022Baird & Brett, 2020(Hall, 1876)Conch geometryExtremely discoidalThinly discoidalThinly discoidalThinly discoidalConch probably(CWI c. 0.25)(CWI c. 0.35)(CWI c. 0.35)(CWI c. 0.35)discoidalWhorl profile stronglyWhorl profileWhorl profileWhorl profileWhorl profile shapecompressedcompressedcompressedcompressedunknown(WWI c. 0.40)(WWI c. 0.65)(WWI c. 0.65)(WWI c. 0.65)Umbilicus closed atUmbilicus closed atUmbilicus closed atDiameter of umbilicalDiameter of umbilical30 mm dm50 mm dm50 mm dmclosure unknownclosure unknownUmbilical marginUmbilical marginUmbilical marginUmbilical marginUmbilical margincontinuously roundedcontinuously roundedobliquely flattenedcontinuously roundedcontinuously rounded(funnel-shaped)Flanks weakly convex, Flanks weakly convex, Flanks nearly parallelFlanks weakly convex,Flanks weakly convexconvergentconvergentconvergentSuture lineNarrow E lobeV-shaped E lobeV-shaped E lobeWide E lobe withWide E lobe withconvex flanksconcave flanksNearly symmetricAsymmetric A lobe,Nearly symmetricAsymmetric A lobe,Asymmetric A lobe,A lobe, wider thanas deep as wide,A lobe, deeper thanslightly wider thanvery deep, deeperdeepconvergent flankswide, parallel flanksdeepthan wide–––Flat-toppedDorsolateral saddledorsolateral saddleless wide
表1. — 1902年弗雷希（Frech）建立的埃皮脱角石属（Epitornoceras）不同物种的形态特征对比。缩写说明：CWI为壳体宽度指数（conch width index）；UWI为脐部宽度指数（umbilical width index）；WER为旋环扩张率（whorl expansion rate）；WWI为旋环宽度指数（whorl width index）。 成年个体形态特征： 1. 壳体几何形态： - 埃皮脱角石E. transmediterraneum（Leanza, 1968）：极度盘形，壳体宽度指数CWI约0.25，成年壳径约30~50 mm - 埃皮脱角石E. dennisoni（Frech, 1888）：薄盘形，CWI约0.35 - 埃皮脱角石E. baldi（Korn & Bockwinkel, 2022）：薄盘形，CWI约0.35 - 埃皮脱角石E. smithracoides（Baird & Brett, 2020）：薄盘形，CWI约0.35 - 埃皮脱角石E. peracutum（Hall, 1876）：推测为盘形 2. 旋环轮廓： - E. transmediterraneum：强烈压缩，旋环宽度指数WWI约0.40 - E. dennisoni：压缩，WWI约0.65 - E. baldi：压缩，WWI约0.65 - E. smithracoides：压缩，WWI约0.65 - E. peracutum：轮廓形态未知 3. 脐部闭合情况： - E. transmediterraneum：脐部闭合，闭合细节未知 - E. dennisoni：脐部闭合，闭合细节未知 - E. baldi：脐部直径对应壳径30 mm - E. smithracoides：脐部直径对应壳径50 mm - E. peracutum：脐部直径对应壳径50 mm 4. 脐缘： - E. transmediterraneum：连续圆形（漏斗形） - E. dennisoni：连续圆形 - E. baldi：斜向扁平 - E. smithracoides：连续圆形 - E. peracutum：连续圆形 5. 侧面形态： - E. transmediterraneum：侧面弱凸且收敛 - E. dennisoni：侧面弱凸且收敛 - E. baldi：侧面近于平行 - E. smithracoides：侧面弱凸且收敛 - E. peracutum：侧面弱凸且收敛 6. 缝合线： - E. transmediterraneum：外叶（E lobe）狭窄，侧翼收敛 - E. dennisoni：外叶呈V形，A叶近对称 - E. baldi：外叶呈V形，A叶近对称 - E. smithracoides：外叶宽大，侧翼凹陷，A叶不对称，宽度大于深度 - E. peracutum：外叶宽大，侧翼凸起，A叶不对称，极深且深度大于宽度 7. 其他特征： - E. transmediterraneum：无相关数据 - E. dennisoni：无相关数据 - E. baldi：无相关数据 - E. smithracoides：平顶 - E. peracutum：具背侧鞍（dorsolateral saddle），背侧鞍较窄
